The invention relates to a positive calibrator/control composition for IgM serology assays and to an IgM serology assay using the positive calibrator/control composition.
Assays for infectious diseases require both negative and positive calibrator and/or control compositions. The negative calibrators typically consist of human sera which are known not to include any of the antibodies of interest. The positive calibrator compositions typically are prepared by spiking the negative calibrators with known amounts of the antibodies of interest which are obtained from human patients. The positive control compositions typically are prepared by spiking the negative calibrators with amounts of the antibodies which are equal to or different from those which are used in the calibrator compositions.
It is well known that the first immune response to an infectious disease agent in an individual is the production of IgM antibodies. However, the IgM immune response occurs only for a very short period of time, e.g., for a few weeks to a few months. The IgG immune response follows and goes on for a relatively long period of time, e.g., a number of years.
Since the first immune response is the production of IgM antibodies, and because IgM antibodies are short-lived, assays for these antibodies are important since such assays can provide an early indication of a recent infection in a patient. However, because of the short duration of the IgM response and the fact that the infectious disease in a patient may not be discovered until the IgM response has ended, it is difficult to obtain a sufficient supply of IgM antibodies from individuals to use in positive calibrator/control compositions for assays for the infectious disease. Further, the procedure for doing so is labor intensive, very lengthy and very costly.
It would be advantageous to have an unlimited supply of antibodies of consistent quality which can be used in the positive calibrator/control compositions for IgM serology assays. Accordingly, it is an object of this invention to provide a positive calibrator/control composition for use in IgM serology assays. It is also an object of the invention to provide an IgM serology assay which utilizes the positive calibrator/control compositions according to the invention.